HNF1B and maturity-onset diabetes of the young: HNF1B haploinsufficiency causes maturity onset diabetes of the young (MODY) including pancreas atrophy, while homozygous disruption of hnf1ba in zebrafish leads to a failure of pancreas development during embryogenesis (Fajans et al. 2001; Sun and Hopkins 2001; Quilichini et al. 2021).